1:   
   2:   
   3:  //imports
   4:  import java.awt.BorderLayout;
   5:  import java.awt.event.ActionEvent;
   6:  import java.awt.event.ActionListener;
   7:  import javax.swing.JPanel;
   8:  import javax.swing.JButton;
   9:  import java.awt.Color;
  10:   
  11:   
  12:   
  13:  // FrameGUI inherits from JPanel and implements ActionListener
  14:  // this allows the program to listen for button clicks
  15:  public class FrameGUI extends JPanel  implements ActionListener
  16:  {
  17:      private JButton btnSetToBlack,btnSetToBlue;
  18:      private BorderLayout layout;
  19:   
  20:      //constructor
  21:      public FrameGUI()
  22:      {
  23:          //instantiate a new BorderLayout with 50 pixel gaps between
  24:          // components of the layoutManager
  25:          layout = new BorderLayout(50,50);
  26:          //set the FrameGUI's layout to the layout defined above
  27:          this.setLayout(layout);
  28:   
  29:          //instantiate the 2 buttons
  30:          btnSetToBlack = new JButton("BLACK");
  31:          btnSetToBlue = new JButton("BLUE");
  32:   
  33:          //add the 2 buttons to FrameGUI (specifying position)
  34:          this.add(btnSetToBlack, BorderLayout.WEST);
  35:          this.add(btnSetToBlue, BorderLayout.EAST);
  36:          //here, the component you are required to make will be added to the gui
  37:          // adding your component -->
  38:          this.add(new DrawComponent(), BorderLayout.CENTER);
  39:   
  40:          //action listeners assigned to buttons (to listen for user actions)
  41:          btnSetToBlack.addActionListener(this);
  42:          btnSetToBlue.addActionListener(this);
  43:   
  44:          //default colours, visiblity and size of frameGUI defined here
  45:          this.setBackground(Color.GRAY);
  46:          this.setVisible(true);
  47:          this.setSize(800,600);
  48:      }
  49:   
  50:      //actionPerformed(ActionEvent event) allows event information to be processed
  51:      //below the event source is checked (i.e. what button was pressed) and the
  52:      //background colour is changed accordingly
  53:      public void actionPerformed(ActionEvent event)
  54:      {
  55:          if (event.getSource() == btnSetToBlack) this.setBackground(Color.BLACK);
  56:          if (event.getSource() == btnSetToBlue) this.setBackground(Color.BLUE);
  57:      }
  58:  }